Human Papillomavirus Antibody Levels Following Vaccination or Natural Infection Among Young Men Who Have Sex With Men.

Background: Australia introduced a school-based gender-neutral human papillomavirus (HPV) vaccination program for girls and boys aged 12-13 years in 2013. We examined HPV type-specific antibody levels in unvaccinated young men who have sex with men (MSM) with natural infection and compared these with levels in those vaccinated against HPV.
Methods: Serum specimens at baseline were collected from MSM aged 16-20 years in the HYPER1 (Human Papillomavirus in Young People Epidemiological Research) and HYPER2 studies, conducted in 2010-2013 and 2017-2019, respectively. Merck's 4-plex HPV competitive Luminex Immunoassay was used to quantify HPV6-, HPV11-, HPV16-, and HPV18-specific antibodies. We compared antibody levels for each HPV genotype between unvaccinated men (HYPER1) and vaccinated men (HYPER2) using the Mann-Whitney U test.
Results: There were 200 unvaccinated men and 127 vaccinated men included in the analysis. Median antibody levels among vaccinated men were significantly higher than levels among unvaccinated men for HPV6 (223 milli-Merck units per milliliter [mMU/mL] vs 48 mMU/mL, P < .0001), HPV11 (163 mMU/mL vs 21 mMU/mL, P < .0001), HPV16 (888 mMU/mL vs 72 mMU/mL, P < .0001), and HPV18 (161 mMU/mL vs 20 mMU/mL, P < .0001). Antibody levels did not change over time for up to 66 months for all 4 genotypes among vaccinated men.
Conclusions: Among young MSM vaccinated with the quadrivalent HPV vaccine, antibody levels for HPV6, HPV11, HPV16, and HPV18 were significantly higher than those in unvaccinated MSM following natural infection. Antibody levels following vaccination appeared to remain stable over time.
Clinical Trials Registration: NCT01422356 for HYPER1 and NCT03000933 for HYPER2.
Competing Interests: Potential conflict of interest . E. P. F. C. is supported by an Australian National Health and Medical Research Council (NHMRC) Emerging Leadership Investigator grant (GNT1172873); reports grant payments to their institution from the World Health Organization and Gilead Sciences; and reports personal payments for educational activities from Roche, Merck & Co., and Gilead Sciences SL. C. K. F. and S. M. G. are supported by an Australian NHMRC Leadership Investigator grant (GNT1172900 and GNT1197951, respectively). E. P. F. C. and A. M. C. have received educational grants from Seqirus Australia and bioCSL to assist with education, training, and academic purposes in the area of HPV outside the submitted work. E. P. F. C. has received an honorarium from Merck Sharp & Dohme and Roche outside the submitted work. C. K. F. has received research funding from CSL Biotherapies and owns shares in CSL Biotherapies. S. M. G. has received advisory board fees and lecture fees from Merck & Co. for work in private time; through her institution (Royal Women’s Hospital), has received funding for an investigator-initiated grant from Merck & Co. for a young women’s study on HPV; is a member of the Merck Global Advisory Board for HPV vaccines; and serves as president for the International Papillomavirus Society. H. Z. is supported by the Natural Science Foundation of China Excellent Young Scientists Fund (82022064), Natural Science Foundation of China International/Regional Research Collaboration Project (72061137001), and the Shenzhen Science and Technology Innovation Commission Basic Research Program (JCYJ20190807155409373). All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.
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